This invention relates generally to filters and methods and more particularly, but not by way of limitation, to filter apparatus and methods for removing particulates from an airstream adapted for use in a paint booth.
Filters, including air filters, are used for a variety of applications. Generally, an air filter fits in a housing and has a filter media which removes undesired particles from a fluid, typically an airstream. Depending on its specific application, the filter media is adapted to remove dust, dirt, paint, fumes and/or other particles.
In paint booths, i.e., paint overspray control or paint arrester applications, a filter is placed in the exhaust airstream of the paint booth or similar structure. Paint spray residual that does not adhere to the article being painted is entrained in the airstream of the exhaust exiting the paint booth. The airstream passes through the filter positioned at an air intake before it is exhausted into the environment.
Generally in paint booths and similar applications, a few types of filters are commonly used. One is a rigid, non-collapsible, framed filter. The framed filter is designed to fit snugly in the modular frame of the exhaust airstream of the paint booth. A rear supporting grid either built into the filter or placed behind the filter in the modular frame is used to prevent the filter from being drawn through the modular frame into the exhaust duct. Another type of filter is a frameless accordion-type filter media typically manufactured in long sections, i.e., twenty to thirty feet long, and cut to length to fit a particular modular frame of the paint booth. The expandable/collapsible filter medium is formed of paperboard, cardboard and/or honeycomb to create an inexpensive and effective filter means. The filter is cut and a rear supporting grid is typically used to secure the filter. Clips or wire fasteners are used to secure the edges of the filter to the modular frame of the air intake.
Another commonly used filter is a corrugated paper baffle type filter. This type of filter typically has one to three filter media layers. The media layers often have a plurality of voids or holes disposed through the media layers. Air carrying particulates is routed through the voids and the particulates are deposited on the media layers. Examples of these types of filters include U.S. Pat. Nos. 3,075,337, 4,008,060 and 5,051,118, which patents are incorporated by reference herein.
While many of these prior art filters work well for their intended application, a cone of the particulate will sometimes form on a secondary media layer directly behind a hole in the first media layer, which is referred to as xe2x80x9cloading.xe2x80x9d These cones of particulate, or loading, reduce the life and efficiency of the filter. Also, a great deal of waste in the form of disks or chads is generated by creating the voids or holes in the filter media. Moreover, it is believed that the overall particulate efficiency and holding efficiency can be improved as compared to the prior art filters.
Thus, there is a need for improved filter apparatus and methods which reduce loading, are voidless, can be efficiently manufactured, can improve overall particulate and have improved holding efficiency.
The present invention provides improved filter apparatus which meet the needs described above.
The invention includes a filter apparatus and method for removing air entrained particulates. A first media member has a pair of upstream folds and a downstream fold interposed between the pair of upstream folds. A wall connects each of the pair of upstream folds to the downstream folds. An aperture is positioned on the wall between the pair of upstream folds and a pleat is hinged to an edge of the aperture.
The invention also includes a filter apparatus and method having a first media member. The first media member has a plurality of alternating upstream folds and downstream folds and a wall connecting the upstream folds to the downstream folds. A pair of slits is cut to the wall and across the downstream folds such that the first media member is voidless in a flat state and such that the pair of slits forms an aperture with a pleat at least partially covering the aperture in a corrugated state.
The invention further includes a method of forming a filter for removing air entrained particulates comprising providing a voidless first media member having a plurality of alternating upstream folds and downstream folds and a wall connecting the upstream folds to the downstream folds. The method also includes cutting a plurality of pairs of slits through the wall and across the downstream folds.
It is therefore a general object of the present invention to provide improved filter apparatus and methods. Other and further objects, features and advantages of the present invention will be readily apparent to those skilled in the art upon a reading of the following disclosure when taken in conjunction with the accompanying drawings.